Swing diffuser



Dec. 8, 1964 Filed Sept. 2l, 1961 L3/ffl /B gli 29 C- W. CHASE SWINGDIFFUSER 2 Sheets-Sheet l EL-gado?? mmfm/w ma@ Dec. 8, 1964 c. w. CHASE3,150,585

SWING DIFFUSER Filed sept. 21, 1961 2 sheets-sheet 2 'EQ-jg A9@ @D @ifQN@ 55 52 Ewa/ufo? nited States Patent Office arenas Patented Dec. 8,1964 3,153,685 SWNG DEFFUSEB Carson W. Chase, @ak Park, ill., assignerto FM@ Corporation, a corporation of Delaware Fiied Sent. 21, i951, Ser.No. 139,703 3 Claims. (Ci. iol-i124) The present invention relates to aswing dfuser for aerating liquid, such as sewage, in a tank, and isparticularly concerned with a piping and linkage arrangement by means ofwhich the aeration is accomplished more emciently than possible withpreviously known apparatus.

Swing dilfusers comprise a stationary header in ow communication with `asource of air under pressure, a pm'r of hanger pipes, and a diffuserheader immersed in the liquid being aerated. In the present applicationthe term upper hanger pipe will refer throughout the speciiication andclaims to the hanger pipe that is uppermost when the swing diffuser isin its operating position with the diffuser header in its lowermostposition. The term lower hanger pipe will always refer to the hangerpipe that is lowermost when the swing diffuser is in said operatingposition.

Heretofore diffuser headers in swing diifusers have been limited to alength of approximately sixteen feet. The excessive weight of units ofgreater length and the loss or" air pressure due to air friction made ituneconomical to supply proper air pressure throughout the length oflonger units. Very large quantities of air are required for treatment inlarge sewage treatment plants. The cost of compressing air is, next tothe cost of labor, usually the largest operating cost. Since cost ofcompressing air is approximately proportional to the compressedpressure, any increased air pressure required at the compressor7 due tofrictional iiow loss between the compressor md the header, increasesboth operating costs and the original cost of air compressing equipment.

Swing diiusers previously known have been characterized by pivotalconnections between the ltwo hanger pipes and between the upper hangerpipe and the stationary header. The meeting surfaces of each of thesepivotal connections are machined to a smooth finish to provide air sealsand to reduce the surface friction between the moving parts. Eachpivotal connection is characterized by a sharp right angle bend in thepassageway for air owing through the diffuser. The right angle bends inthe direction of air flow at the pivotal connections cause considerableair friction in the swing diffuser.

In accordance with the present invention the pivotal connections of theupper and lower hanger pipes cornmon to swing diiusers of the prior artare replaced by exible connections. The liexible connections are formedby flexible tubes and by pivoted guide members that help control thepivotal movement of the hanger pipes. One iiexible tube has one endsecured to an outlet in ilow communication with an air main or othersource of air p under pressure, and its other end secured to the upperend of the upper hanger pipe. The other flexible tube has one endsecured to the lower end of the upper hanger pipe and its other end tothe upper end of the lower hanger pipe.

The flexible tubes providing the connection between the upper hangerpipe and the air source and between the upper and lower hanger pipes arepreferably plastic or elastomeric. The tube connecting the upper hangerpipe to the source of air is provided with a flexible steel shield thatprotects it from deterioration due to the suns rays and also prevents itfrom buckling too sharply in the center of its bend.

The flexible connections of the hanger pipes permit the air to flowsmoothly from the air main to the T fitting at the diffuser header in asingle vertical plane. The smooth liow path for the air eliminates asubstantially large pressure loss due to air friction in the pivotaljoints of swing dilfusers of the prior art. The exible tubes also reduthe total weight of the swing diffuser. The

K decrease in weight and the reduction in pressure loss permit the useof diffuser headers of approximately twice the maximum length heretoforeused. T he use of longer headers permits the diffusion of more air fromeach swing assembly, and therefore fewer swing assemblies are requiredin a tank. The use of fewer swing assemblies per tank reduces both thecost of installation and the maiutenance cost for the diffuserequipment. Y Y

The flexible tubes also eliminate the need for expensive machining ofthe meeting surfaces at each of the pivotal joints. The elimination ofthe pivotal joints having surface to surface contact between smoothlymachined surfaces also eliminates the need of lubricating the parts atsaid joints. The flexible tubes are secured to the ends of the pipes toform airtight seals. The ends of the pipe sections are spaced from eachother, and all metal to metal contacts are eliminated from thepassageway through which the air ows.

The guide members cooperate with the hanger pipes to restrict themovement of the hanger pipes toa single vertical plane. The upper guidemember is a rigid structure having one end rigidly secured to the upperhanger pipe adjacent its upper end and the other end pivotally securedto a stationary anchor member to form a swing joint. The lower guidemember, which comprises a knee assembly for the joint between the hangerpipes, is a pivoted structure having one section rigidly secured to theupper hanger pipe adjacent its lower end and another sction rigidlysecured to the lower hanger pipe adjacent its upper end.

A rigid control bar connecting the stationary anchor member and the kneeassembly controls the relative positions of the upper and lower hangerpipes throughout their range of movement between their upper, orservicing, position and their lower, or operating, position. The

lower end of the control bar is pivotally secured to theV lower sectionof the knee assembly. The upper end of the control bar is pivotallysecured to the stationary anchor member. The pivotal connections of thecontrol bar to the stationary anchor member and lower guide member areso located, relative to the pivots about which the guide members areadapted to swing, that straight lines connecting the four pivot pointswithout crossing forma parallogram in all positions of the hanger pipesexcept the dead center position in which all four pivot points are inalignment.

The four pivot points are so arranged Vthat when the swing assembly isbeing raised, the pivot points do not move into alignment until thediffuser header has been lifted above the liquid level of the tank. lfthe diffuser header is still immersed in the liquid of the tank when thepivot points move into alignment, the direction of the pivotal movementof the lower hanger pipe from the dead center position is not certain.`The buoyancy of the header, together with forces exerted by fluidcurrents in the tank may reverse the direction of the pivotal movementof the lower hanger pipe as the pivotal movement of the upper hangerpipev is continued past the dead center position in which the hangerpipes are extended with all pivot points aligned. Such reversal willcause the lower hanger pipe to swing outwardly instead of inwardly asthe upper hanger pipe is moved upwardly past dead center position. Suchoutward movement of the lower hanger pipe will not move the diffuserheader into its servicing position, and will probably damage themechanism.

lf the diuser headeris clear of the liquid at the time the four pivotpoints move into alignment, the direction diffuser header makes itnecessary to provide means sta-V bilizing the header against the varyingor fluctuating forces of buoyancy and of fluid currents in which it isimmersed. Such means may comprise legs, tie rods, latch means, etc., ora combination of such means.

. Legs or tie rods prevent the header from sagging in a dry tank, andare adjusted (in a dry tank) to produce Y an upward force on theV headerand a resulting, resisting,

elastic bending moment in the header structure inboard of the point ofattachment.

Even in the case of a long, flexible, buoyant header, the lifting effectof buoyancy and fluid current forces is resisted by the said resistingelastic bending moment so that the leg is not lifted; nor is the pointof attachment of the tie rod lifted. Thus, at the point of leg or tierod attachment, the header is not deflected upward by buoyant or currentforces. Upward header deflection is limited-to the free length of headerand is greatly'reduced by the reduced free header length. ln the case ofleg the legs therefore remain in firm stabilizing Contact with the tankfloor.Y

Consequent reduction of header deflection makes it possible to adjustVthe entire length of header to essentially the same depth ofsubmergence. Deiiection of the header amounting to no more than twoinches impairs uniformity of air distribution because of the dilferencein water pressure at different depths.

Rollers are mounted to form the lower end of the legs to facilitatemovement of the dilfuser header to its desired position.

If tie rods are used in combination with legs, the tie rods prevent thelegs from dropping as the header is raised and the force exerted upwardon the legs at the floor of the tank drops off. Thus, the tie rodsreduce the length of rolling of the rollers as the header is raised orlowered and also reduce the 4force which must be supported by therollers.

Instead of having supporting legs intermediate the length of thediffuser header, the header may be held in proper position by suitablelatch means. When latches are used they are positioned to engagetheheader at points spaced to prevent deliection of the header.

The structure by means of which the above noted and other advantages ofthe invention are atained will be described in the followingspecification, taken in conjunction with the accompanying drawingsshowing a preferred embodiment of the invention, in which:

FIG. l is a side elevational view of a swing diffuser embodying theinvention, with the diffuser in its lowermost or operating position;

FIG. 2 is a fragmentary front elevational View of the swing diffusershown in FIG. l;

FIG. 3 is a fragmentary front elevational view of a swing diffusershowing cables attached to the fitting adjacent the diffuser header toprevent the header from swaying;

FIG. 4 is a fragmentary front elevational view of a latching mechanismfor holding the diffuser header against swaying;

FIG. 5 is a cross sectional View of the latching mechanism of FIG` 4;

FIG. 6 is a fragmentary top plan view showing the means for securing oneend of the shield to a fixed support;

FIG. 7 is a fragmentary side elevational view of the i structure of FIG.6 with the apparatus in operating position; and

FIG. 8 is a view similar to FIG. 7 with the apparatus in servicingposition.

Referring to the drawings, a tank 2 comprising a floor 3 and a pluralityof vertical walls 4 has a coping 5 extending from the upper edge of onevertical wall to provide a groove o in which an air main '7 ispositioned. Air main 7 is provided with an outlet 8 extending toward theupper edge of the coping. The specific arrangement of the air main isillustrated merely as an example of a suitable structure for use withthe swing iffuser, and it will be understood that neither the structureof the tank nor the specific arrangement of the air main is consideredto constitute any part of the invention.

A. stationary anchor member 9 is mounted in fixed position on the upperedge of coping S adjacent outlet 8. The anchor member 9 is fixed tocoping 5 by any suitable Y means. It may be embedded in the concreteforming the wall, or may be lixed by bolts or similar fastening means.The anchor member is preferablyy formed of metal plates, but may be castor molded of any suitable material. As shown in the drawings, anchormember 9 comprises two side Walls 10 and il connected at one side by anintegral bridge member l2. rl`he lower edge of bridge member 12 islocated in a. horizontal plane above the horizontal plane of the upperedge of the coping and is spaced on the side of anchor member 9 closestto the air main 7.

An upper guide member in the form of a bridle i3 is pivotally secured toanchor member 9 by pins or studs 14 and 15 to form a swing joint for anupper hanger pipe 15. Bridle 13 is a rigid assembly comprising sidewalls 17 and i8 connected by an integral bridge member i5? and a plateZtl at the lower ends of the side walls. Plate Ztl is apertured to fitaround the upper end of upper hanger pipe le to whichit is permanentlysecured. Pin 14 extends through side walls l@ and 17, and pin i5 extendsthrough side walls 11 and 18 to provide a fixed pivot for bridle i3which moves pivotally in a vertical plane. Bridge member 19 extendsapproximately vertically on the side of bridle 13 most remote fromcoping 5 when the Y 'diffuser is in its lowermost position.

An upper flexible tube 2l has one end sealed to outlet 8 and its otherend sealed to the upper end of upper hanger pipe le to form a flexiblejoint between the air and the upper hanger pipe. Tube 2l may be made ofany suitable plastic or rubber composition and may be reinforced, ifdesired. One example of a suitable material for the flexible tubecomprises nylon coated on both surfaces with neoprene. Thereinforcement, if used, is preferably embedded in the nylon, and maycomprise a helically wound wire or a plurality of wire rings spacedlongitudinally of the tube. lt is also possible to provide integralannular ribs as reinforcement for the tube. The reinforcement, if used,must not impair the ilexibility of the tube. Flexibility is an essentialcharacteristic of the tube because the tube must provide a ilexiblehinge for the eswingjoint and for the joint between the upper and lowerhanger pipes.

Upper hanger pipe i6 is in the same vertical plane as outlet 8, andupper flexible tube 21 provides a passageway for a smooth ow of air fromthe outlet to the upper hangerpipe. The upper exible tube extendsbetween side walls 1t? and l1 of anchor member 9 and between side walls17 and 1S of bridle 13. Bridle i3 is rigidly attached to upper hangerpipe lr6 in any suitable manner, as, for example, by welding. Anchormember 9 and bridle 13 cooperate to prevent lateral displacement of tube21 and maintain it in the same vertical plane as outlet 8 and upperhanger pipe 16.

The end portion of upper flexible tube 2l adjacent outlet 8 extends overthe upper edge of coping 5 between the side walls of anchor member 9.Bridge member 12 is spaced far enough from the edge of coping 5to permitthe upper flexible tube to extend through the space between the loweredge of bridge member 12 and the outer upper edge of coping 5. Levelingscrews 22 are provided to hold anchor member 9 at the desired heightrelative to the top of coping 5. Ametal plate 23 embedded in copingcooperates with screws 22 to hold the anchor member in place. Y

A flexible shield 25, preferably of metal, is mounted to engage one sideof ilexible tube 21. The shield protects the upper flexible tube 21 fromthe sun and also prevents -it from bending too sharply. One end ofshield 25 is secured to bridge member 19 in any suitable manner. Theother end of shield 25 is connected to outlet S by a pair of links 26and a pair of springs 27 as shown in FIGS. 6, 7 and S. Each spring 27has one end pivotally secured to a pin 28 projecting laterally fromoutlet 3. The outer end of each pin is preferably `in the shape of aring 28 for engagement with a loop 27 formed on the end of the springsecured thereto. Each link has a hookshaped end 26 to engage a loop 27"formed on the other end of spring 27. The end of shield 25 to whichlinks 2d are secured is preferably reinforced by a rigid strip 25.

When the swing assembly is in operating position springs 27 are undertension, as shown in FIG. 7, and hold shield 25 against the uppersurface of flexible tube 21. As the swing assembly is moved towardservicing position, the shield 25 is pushed toward the air main 7 by thebending movement of flexible tube 21, thus contracting springs 27. Thepivotal connections of links 26 permit them to move pivotally about theloops 27 into the position shown in FIG. 8. In this position, springs 27exert tension on the links in the opposite direction from that shown inFIG. 7. The springs hold shield 25 against the upper surface of ilexibletube 21 and thereby prevent tube 21 from bending too sharply as theswing assemby is moved toward its servicing position. The control of thecurvature of the upper exible tube 21 maintains a smooth passageway forthe ow of air from outlet 8, and thereby minimizes air friction andreduces pressure loss as the air flows through the tube when the swingassembly is in either its operating position or in its servicingposition.

The lower end of upper hanger pipe 16 is connected to the upper end of alower hanger pipe 29 by a lower tlexible tube 31'? that forms a exibleknee joint. Lower flexible tube 39 and lower hanger pipe 29 are in thesame vertical plane as upper hanger pipe 16 and upper eXible tube 2l.Tube 30 is similar to tube 21 but does not require a shield, such asshield 25, because it is not exposed to the sun continuously, as in thecase of tube 21.

A pivoted lower guide member 31 prevents lower flexible tube 36 frombeing kinked when it is bent in either direction by the relativemovement between the upper and lower hanger pipes. Guide member 31comprises an upper section 32 and a lower section 33. Upper section 32has two side walls 34 and 35 connected by an integral strip 36 adjacenttheir upper edges and an end plate 37. Side walls 34 and 35, strip 36and plate 37 are fastened together and to upper hanger pipe 16 by meanssuch as welding. Bridle member 13, upper hanger pipe 16 and uppersection 32 of guide member 31 therefore comprises a light but strong andrigid assembly having one end pivoted at 14, 15, and the other endpivoted at 39, 4t), by pivot pins spaced to insure lateral stability inthe plane of PG. 2. Lower section 33 of lower guide member 31 comprisesside walls 41' and 42 connected by an integral strip 43 adjacent theirlower edges and an end plate 44. An intermediate plate secured to walls41 and 42 provides additional stitfening of walls 41 and 42.

Side walls 4l and 42, strip 43 and plate 44 are fastened togetherrigidly and to pipe 29 by means such as welding. A ange 45 is threadedor welded to the lower end of pipe 29. T hereiore, lower section 33 oflower guide member 31 and lower hanger pipe 29 comprise a light, strong,and rigid assembly pivoted to the upper pipe assembly at 39 t and 423.Pin 39 pivotally connects side walls 34 and 4i and pin 40 pivotallyconnects side walls 35 and 42.

Side wall 42 extends upwardly past pivot pin 4t? and is pivotallyconnected, as indicated at 47, to the lower end of a rigid control bar48. Control bar 43 is curved at approximately 90 adjacent its upper end,as indicated at 49. The control bar 48 is pivotally connected to anchormember 9, as indicated at 59. The pivotal connections between the hangerpipes, the control bar, the stationary anchor member and the kneeassembly are so positioned that straight lines between the pivot points14 and Sil, 5t) and 47, 47 and 39, and 39 and 14 form a parallelogram inall positions of the swing assembly except in the dead center positionin which said pivot points are in alignment. The above describedrelationship between the various pivot points of the swing assemblyprovides a positive control for the lower hanger pipe to keep itsubstantially vertical throughout its movement as well as when it is ineither operating or servicing position. The unit may be locked in itsoperating position without requiring any extra weights secured to theheader for counteracting the buoyancy of the liquid in which it isimmersed. The uniform vertical position of the lower hanger pipe insuresaccurate placement of the dittusers in the tank when the swing assemblyis in operating position, and insures accessibility of the headers whenthe swing assembly is in servicing position.

The swing assembly is lifted from its operating position to itsservicing position by a lifting force applied to the rigid upper pipeassembly by a hoist or any other suitable means. The upper pipeassembly, comprising upper hanger pipe 16, bridle 13 and upper section32 of guide member 31, is swung upwardly about pivots 14, 15 incounterclockwise direction, as seen in FIG. 1. The upward pivotalmovement of the upper pipe assembly carries the lower pipe assemblyupwardly, and, as the upper pipe assembly swings outwardly about itspivots 14, 15, the lower pipe assembly moves pivotally about pivots 39and 47 in clockwise direction.

A diuser header 51, comprising two sections 52 and 53 is secured to thelower hanger pipe by means of a T- nipple S4 secured to the lower end oflower hanger pipe 29. A plurality of air diusers 55 mounted on dituserheader 51 are spaced longitudinally of the diffuser header. Although theshowing in FIG. 3 indicates that air ditfusers 55 extend laterally ofthe header, it will be understood that the air ditfusers may be mountedon the diffuser header in any desired manner. The diffuser header has alength approximately twice the length ot diffuser headers heretoforeused. The added length of diuser header is made possible by the use ofthe exible tubes that eliminate the right angle bends of air passagesthrough the pivotal connections conventionally provided between the pipesections ot dituser structures of the prior art. The elimination of theright angle bends in the air passageway reduces the friction loss tosuch an extent that a greater flow of air is attained at a givencompressor discharge pressure, thus providing uniform distribution ofair throughout the diuser headers of twice the conventional lengthwithout requiring excessive air pressure at the compressor.

The header is supported on the bottom of the tank by support legs 56provided with wheels 57 rotatably mounted in their lower ends. Thewheels facilitate moving the header into proper position. The wheelsfurnish enough upward force to cause a torque at the center of theheader that urges the ends of the header downwardly against the upwardforce of the wheels and keeps the wheels down against the bottom of thetank. Tie rods 58 extending between the lower'hanger pipe 29 and eachsection 52, 53 of the header lift the ends of the header to keep themparallel against sagging in a dry tank. The wheels do not touch thebottom of the tank until they reach their iinal position. If the headerwere allowed to sag, the wheels would drag across the bottom of thetank.

The wheels on the support legs and the tie rods co- 6' operate tosubstantially eliminate de'iection of the header. Deliection of theheader of as little as two inches impairs the uniformity of airdistribution because of the difference in water pressure at differentheights of the' header. When tie rods and wheels are provided, the onlydeection of the diffuser header that can occur is at the ends of theheader and is too small to matter.

The embodiment of the invention shown in FIG. 3 is substantially thesame as that of FIGS. 1 and 2 except that the tie rods and support legsare omitted. la this: embodiment, exible cables 59 anchored at one endto` coping 5 have their opposite ends secured to a ring 60 attached tolower hanger pipe 29 adjacent iiange 46, Cables 59 prevent swaying ofthe diiuser header. When cables are provided, no extra weights arerequired to hold. the header in place. The header is adjusted so thatits ends sag in a dry tank. When the header is immersed in liquid thebuoyancy of the liquid raises the ends of the. header enough to make theheader lie parallel to the bottom of the tank throughout its length.

In the embodiment of FIGS. 4 and 5, the diffuser header 51 is held inits down position by a roller latch comprising an upright standard 51and a roller 62. Standard 61 is anchored to the iioor 3 of the tank 2 inany suitable manner, as, for example, by means of bolts 63. Roller 62 isrotatably mounted adjacent the top of the standard, as indicated at 64.The lowermost peripheral surface of roller 62 is spaced above the iioorof the tank a distance equal to the desired distance of the uppersurface of the diffuser header 51 from licor.

Standard 61 is notched, as indicated at 65, to provide a shoulder 66upon which the diffuser header is adapted to be seated. Notch 65preferably extends rearwardly of axis 64 a distance slightly greaterthan the external radius of diffuser header 51. When the swing assemblyis in its lowermost or operating position the diffuser header is pushedinto notch 65. The depth of notch 65 permits the diffuser header to bemoved to a position in which its longitudinal center is past thevertical plane of the axis 64. In this position the diiuser header isheld iirmly in the desired position because the lowermost portion of theperiphery of roller 62 is slightly forward of and below the uppermostportion of the periphery of diliuser header 51. Although the diffuserheader may be forced out of notch 65, the pressure of roller 62 againstheader 51 prevents accidental displacement of the header. The header isheld firmly on shoulder 66 at the desired height for efficient aerationof the tank.

While I have described a few preferred embodiments of the invention inconsiderable detail, it will be understood that the description thereofis intended to be illustrative, rather than restrictive, as many detailsof construction may be modied or changed without departing from thespirit or scope of the invention. Accordingly, I do not desire to berestricted to the exact construction described.

I claim:

1. In combination, a sewage tank having a floor and a standardprojecting upwardly from said door, one vertical face of said standardhaving a notch therein, a swing diffuser comprising a rigid upper hangerpipe connected 1: to a source of air under pressure, a rigid lowerhanger pipe, a flexible tube connecting the upper end of said lowerhanger pipe to the lower end of said upper hanger pipe, a diiuser headerconnected to said lower hanger pipe, said tube cooperating with saidpipes to form a passageway for the tiow of air from said source to saiddiffuser header, said notch being dimensioned and shaped to receive saiddiuser header, and a roller on said standard to hold said diffuserheader in said notch.

2. In combination, a sewage tank, a swing diffuser comprising a rigidupper hanger pipe connected to a source of air under pressure, a rigidlower hanger pipe, a flexible tube connecting the upper end of saidlower hanger pipe to the lower end of said upper hanger pipe,

means for providing movement of said hanger pipes, a

diffuser header connected to said lower hanger pipe, said tubecooperating with said pipes to form a passageway for the ow of air fromsaid source to said diffuser header, guide means cooperating with saidupper and lower hanger pipes to restrict the movement of said hangerpipes to a single vertical plane, and cables secured to said lowerhanger pipe and the upper edge of said tank to hold said diffuser headerin lixed position above the door of said tank.

3. ln combination, a sewage tank, a swing assembly pivotally mountedadjacent the upper edge of said tank, said assembly comprising an upperhanger pipe flexibly connected to a source of air under pressure, alower hanger pipe flexibly connected to said upper hanger pipe, adiffuser header secured to said lower hanger pipe, and a roller latchfor holding said diffuser header in fixed relationship to said tank,said roller latch comprising a standard projecting upwardly from thefloor of said tank, one edge of said standard having a notch, the loweredge of .said notch forming a shoulder on said standard, and a rollerrotatably mounted on said standard above said notch, the lowermostperipheral edge portion of said roller being spaced above said shouldera distance slightly less than the outside diameter of said ditfuserheader and forwardly of the back wall of said notch a distance slight-`ly greater than the radius of said diffuser header, whereby saiddiffuser header may be positioned in said notch between said shoulderand said roller, with its uppermost peripheral edge portion rearwardlyof and slightly above the lowermost peripheral edge portion of saidroller.

References Cited in the lile of this patent UNITED STATES PATENTS1,219,049 Sticklin Mar. 13, 1917 1,473,160 Robbins Nov. 6, 19232,152,871 Charland Apr. 4, 1939 2,444,800 Aab July 1948 2,453,319Hollyday Nov. 9, 1948 2,521,474 Morgan Sept. 5, 1950 2,527,097 KatowOct. 24, 1950 2,650,810 Nordell Sept. 1, 1953 2,825,541 Moll et al. Mar.4, 1958 FOREIGN PATENTS 346,270 Great Britain Apr. 7, 1931 614,617Canada Feb. 14, 1961

1. IN COMBINATION, A SEWAGE TANK HAVING A FLOOR AND A STANDARDPROJECTING UPWARDLY FROM SAID FLOOR, ONE VERTICAL FACE OF SAID STANDARDHAVING A NOTCH THEREIN, A SWING DIFFUSER COMPRISING A RIGID UPPER HANGERPIPE CONNECTED TO A SOURCE OF AIR UNDER PRESSURE, A RIGID LOWER HANGERPIPE, A FLEXIBLE TUBE CONNECTING THE UPPER END OF SAID LOWER HANGER PIPETO THE LOWER END OF SAID UPPER HANGER PIPE, A DIFFUSER HEADER CONNECTEDTO SAID LOWER HANGER PIPE, SAID TUBE COOPERATING WITH SAID PIPES TO FORMA PASSAGEWAY FOR THE FLOW OF AIR FROM SAID SOURCE TO SAID DIFFUSERHEADER, SAID NOTCH BEING DIMENSIONED AND SHAPED TO RECEIVE SAID DIFFUSERHEADER, AND A ROLLER ON SAID STANDARD TO HOLD SAID DIFFUSER HEADER INSAID NOTCH.
 2. IN COMBINATION, A SEWAGE TANK, A SWING DIFFUSERCOMPRISING A RIGID UPPER HANGER PIPE CONNECTED TO A SOURCE OF AIR UNDERPRESSURE, A RIGID LOWER HANGER PIPE, A FLEXIBLE TUBE CONNECTING THEUPPER END OF SAID LOWER HANGER PIPE TO THE LOWER END OF SAID UPPERHANGER PIPE, MEANS FOR PROVIDING MOVEMENT OF SAID HANGER PIPES, ADIFFUSER HEADER CONNECTED TO SAID LOWER HANGER PIPE, SAID TUBECOOPERATING WITH SAID PIPES TO FORM A PASSAGEWAY FOR THE FLOW OF AIRFROM SAID SOURCE TO SAID DIFFUSER HEADER, GUIDE MEANS COOPERATING WITHSAID UPPER AND LOWER HANGER PIPES TO RESTRICT THE MOVEMENT OF SAIDHANGER PIPES TO A SINGLE VERTICAL PLANE, AND CABLES SECURED TO SAIDLOWER HANGER PIPE AND THE UPPER EDGE OF SAID TANK TO HOLD SAID DIFFUSERHEADER IN FIXED POSITION ABOVE THE FLOOR OF SAID TANK.